Lindt & Spruengli said its factory in Olten had a minor problem with the cooling ventilation system for roasted "cocoa nibs", a key part of chocolate production, last week.
Whipped up by strong winds on Friday morning, the cocoa powder spread around the area near the factory, leaving a fine cocoa dusting on the town, which is located between between the larger cities of Zurich and Basel.
One car was lightly covered in the powder, the company said. It added that it has offered to pay for any cleaning needed but hasn't yet been taken up on the offer.
The particles were completely harmless to people or the environment, Lindt said.
Factory work carried on as normal despite the malfunction and the ventilation system has now been repaired, the company added.
